The motor side of the pump will be full of carbon dust from wear of the brushes. It’s a common problem. Starts as an intermittent loss and sometimes it sticks on even when the car is off and drains the battery. It will pack in soon!

I took mine apart and cleaned it up and have it as a spare. Worked perfectly while I waited for the new one. Relatively easy to take apart, clean and even replace the parts if needed. I wouldn’t of bought a new one if I had of took it apart before I had ordered the new one.